1. Field of the Invention
The present invention relates generally to a powered brake system, and more particularly to a powered brake system with an anti-skid device.
2. Description of the Prior Art
In general, the communication between a control valve and wheel brake cylinders is cut off by an anti-skid device for a powered brake system according to a skid condition and the brake fluid pressure is drained to a reservoir. Thereby, the brake fluid pressure is controlled and the anti-skid operation is attained. However, in such a system the quantity of fluid pressure for the wheel brake cylinders is small, such that control of the fluid pressure speed to the wheel brake cylinders is difficult, and it is generally required that an orifice be disposed between the anti-skid valve and the reservoir. Furthermore, it is generally required that a second orifice be disposed between the control valve and the ant-skid valve. Since the second orifice is disposed between the control valve and the anti-skid valve, transmission of the fluid pressure into the wheel brake cylinders is delayed by such second orifice during a normal braking operation. Therefore the response during a normal braking operation becomes extremely reduced. In order to eliminate this drawback, an electromagnetic valve is in addition provided between the control valve and the anti-skid valve, and the fluid pressure going into the wheel brake cylinders is passed through the second orifice only upon the anti-skid actuation and under normal operation is bypassed. However, in such a system, the electromagnetic valve must be additionally provided.